Supported Attributes:
| Attribute | Description | 
|---|---|
| id | This attribute is a hyphen-separated string, consisting of a prefix This attribute is sg-sp and a sequential number. For example: sg-sp-1. | 
| unit | This attribute specifies the length unit for the polygons in the ClosedShell geometry--Feet for imperial or Meters for metric. | 
Supported Children:
| Element | Description | 
|---|---|
| ClosedShell | This element describes a collection of faces that make up a closed shell. It contains a series of polygons (PolyLoops) defining an enclosed volume. The volume is measured by the interior bounding surfaces for a space. It forms a solid body, which also defines the value of the volume specified for each space. | 
Sample:
<ShellGeometry id="sg-sp-1-Room" unit="Feet">
+ <ClosedShell>
</ShellGeometry>